The term test – short answer – scheduled for lecture time period on February 17, just before Reading Week. Jan. 25, Lecture 7. Squid mantle hydrostat Asterias tube feet; pulsate jet propulsion jellyfish Body waves: Nereis parapodia Snake locomotion Adhesive locomotion: gastropods.
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period on February 17, just before Reading Week
Squid mantle hydrostat
Asterias tube feet; pulsate jet propulsion jellyfish
Body waves: Nereisparapodia
Adhesive locomotion: gastropods
Last year’s two-way table re mantle function: there is an error: ’Volume decreases to 75% of relaxed volume’: should be 75% of relaxed diameter
Santos, R. et al. 2005. Adhesion of echinoderm tube feet to rough surfaces. J. exp. Biol. 208: 2555-2567.Fig. 6 external morphology of unattached pedal discs of Paracentrotuslividus(left) [sea urchin] and Asteriasrubens[starfish](right) .
End of extensible cylinder is the disc, larger in diameter
than the stem. There is a central depression.
The epidermis of the disc contains glands which produce two secretions: glue/bonder and de-bonder, i.e., adhesive secretions and de-adhesive secretions. The glue is delivered through the disc cuticle to the substratum where it forms a thin film bonding the foot . The debonding secretions are released within the cuticle [how?] and act as enzymes; detaching the upper coat of the glue and leaving the rest of the adhesive material behind attached to the substratum as a footprint.
Pulsate jet swimming in jellyfish: pushes it in opposite direction of jet;cancellation parallel to destructive interference in sound production?
Polyp and medusa morphs Power and recovery strokes Incompressible fluid displaced: jetting seawater out from under umbrella
Radial and circular fibres of myoepithelium;
Stores elastic strain energy like ligament of scallop.
Nereissucciniaepitoke of polychaete worm
Retrograde vs direct body waves
Errant polychaetes, parapodia; aciculum [small pin]
Circular oblique retractor (antagonist not another muscle: but coelomicfluidand longitudinal muscles, fenestrated septa
Notopodium, neuropodium [noto = back]
Only when certain portions of the body
wave are in contact with the substratum
From Wikimedia Commons
Arionater, black slug